1. Field of the Invention
The present invention concerns a catheter introducer hemostatic valve which is utilized for diagnoses and treatments by means of blood vein imaging.
2. Description of the Related Art
A catheter introducer has heretofore been utilized as a tool for inserting a blood vein imaging catheter into a blood vein. FIG. 5 shows a profile view of said catheter introducer. In the FIGURE, (1) is a blood vein, (2) is an incision, (3) is a catheter introducer, (5) is its sheath, (6) is its director, (7) is a guide wire, and, (8) is a catheter.
During surgery, the skin in the vicinity of the objective blood vein (1) is cut, and as a result, the incision (2) is formed. After a hollow needle (not indicated in the FIGURE), into which an inner needle (not indicated in the FIGURE) has been inserted, has been introduced into the blood vein (1) via the incision (2), the inner needle is removed. After the guide wire (7) has been inserted into the hollow needle, the hollow needle is removed in such a way that only the guide wire will remain. Subsequently, the catheter introducer (8), into which the director (6) has been inserted, is inserted into the blood vein (1) by using the guide wire (7) as a guide. After the sheath (5) of the catheter introducer has been inserted into the blood vein (1), the director (6) and the guide wire (7) are removed. After the catheter (8) has subsequently been inserted into the sheath (5), the front end of the catheter is guided into the blood vein (1), and as a result, the insertion of the catheter (8) into the blood vein (1) is completed.
During the aforementioned process whereby the catheter (8) is inserted into the blood vein (1), the following problem is observed. For example, if the catheter introducer (3) is inserted into the blood vein (1), if the director (6) and guide wire (7) are removed while the sheath (5) remains in the blood vein (1), and if the catheter (8) is inserted into the catheter introducer (3) and then guided to the blood vein (1), the blood in the blood vein (1) may leak from the catheter introducer (3) as a result of a back flow. To prevent this, a hemostatic valve is attached to the catheter introducer mainframe (4).
FIG. 6 shows an example of conventional hemostatic valves. In FIG. 6, (a) shows a cross-sectional view of the mainframe, whereas (b) shows an oblique view of the hemostatic valve. The hemostatic valve is obtained by inserting a laminate consisting of the valve membrane (9), which possesses the small hole (9a) at the center, and the valve membrane (10), which possesses the Y-shaped slit (10a) at the center, into a gap between the lid (4a) and cylindrical frame (4b) of the mainframe (4). Both the valve membranes (9) and (10) are composed of an elastic material, and since the small hole (9a) and the slit (10a) are present at the center, the valve membranes (9) and (10) are elastically gravitated toward the outer circumferences of the guide wire (7) and catheter (8) when the guide wire (7) and catheter (8) are transmitted through the valve membranes (9) and (10). As a result, the leakage of blood within the mainframe (4) can be prevented, and when the guide wire (7) and catheter (8) are removed, the slit (10a) of the valve membrane (10) is contiguously attached, and as in the aforementioned case, the leakage of blood in the mainframe (4) can be prevented. The hemostatic valve of a catheter introducer serves the aforementioned functions.
In addition to the embodiment of a valve membrane for a catheter introducer hemostatic valve obtained by laminating multiple valve membranes shown in FIG. 6, it is also possible to laminate three valve membranes (11), (12), and (13), which possess the slit (lla), small hole (12a), and the U-shaped channel (13a), respectively (see FIG. 7).
Instead of laminating multiple valve membranes for constituting a catheter introducer hemostatic valve, as in the aforementioned case, there have been many cases in recent years where the functions of multiple valve membranes are assumed by a single valve membrane. Such an example is shown in FIGS. 8 and 9. In the FIGURE, (a) shows an oblique view, and (b) shows a cross-sectional view of the A--A segment. In the valve membrane (14) shown in FIG. 8, the basin-shaped depression (14a) is formed on one surface, whereas the slit (lb) is formed on the other surface, and the center of the depression (14a) and the center of the slit (14b) are linked via the small hole (14c). In the valve membrane (15) shown in FIG. 9, linear slits (15a) and (15b), which perpendicularly intersect one another, are formed on both surfaces. Thus, various structures have been proposed for catheter introducer hemostatic valves.
As has been mentioned above, various types of catheter introducer hemostatic valves have been proposed. The following are necessary conditions for hemostatic valves: (1) there may be no leakage of blood, etc. even when a small-diameter guide wire is transmitted; (2) a large-diameter director or catheter must be smoothly inserted and retracted without resistance; (3) there may be no leakage even in a state where nothing has been inserted.
The aforementioned hemostatic valves obtained by laminating multiple valve membranes somewhat satisfy the aforementioned conditions. When a large-diameter cylinder is repeatedly inserted and retracted, however, the valve begins to fail to fit tightly, and when the cylinder is removed, leakage may be observed. If the thickness of the valve membrane is enlarged in order to prevent said leakage, the leakage can be reduced, but since the inserting resistance increases, the operation becomes difficult.
In the integrated valves shown in FIGS. 8 and 9, some improvements are made as compared with the laminated valves. When a guide wire is quickly inserted and retracted, however, leakage tends to occur, and it is difficult to sufficiently lower the insertion resistance of a large-diameter cylinder. In particular, when a small-diameter guide wire is inserted into the valve membrane shown in FIG. 9, the presence of the slit intersection in the middle, which tightens the guide wire, is more advantageous as compared with a valve which possesses a slit which is open to both surfaces. Even in this case, however the gap (16) is produced, as FIG. 9 (c) indicates, and leakage is inevitable.